It is a common building technique in the construction of wood and composition roofs to provide a zinc-containing metal strip along the side of a roof ridge to prevent fungus and moss growth on the roof surface below the strip. The zinc-containing metal strip is nailed to the upper course of roofing and then the ridge cap is applied over upper course such that it overlays the upper edge of the metal strip. The major portion of the metal strip extends down beyond the edge of the cap and is exposed to the atmosphere. The zinc-containing metal strip is susceptible to spontaneous erosion by rainwater; the rainwater, serving as an electrolyte, dissolves the zinc. The zinc is converted into an oxide that is washed down to bathe the roof surface below the metal strip.
Until the present invention, there has been no comparable system available for tile roofs. Such roofs are made of interlocked or overlapped tile members. These members, whether made of clay or concrete or plastic, are monolithic. Fasteners such as nails cannot be driven into these members. Such members are either too hard or too fragile to be nailed into. Therefore, the use of a zinc-containing metal strip, which heretofore was nailed into the upper course of the roofing, could not be successfully fastened to the upper tile course.